title: Diagnosis of liver metastases: can diffusion-weighted imaging (DWI) be used as a stand alone sequence?
abstract: OBJECTIVE
  To evaluate if diffusion-weighted MRI (DWI) can replace gadolinium-enhanced MRI (Gd-MRI) for diagnosing liver metastases. The diagnostic accuracy of both techniques alone and in combination are compared.
  
  
  METHODS
  Sixty-eight patients with histologically proven primary extrahepatic tumors were included in this retrospective study. Lesions included 62 metastases and 130 benign lesions. Three image sets (unenhanced T1 and T2/gadolinium enhanced T1 (Gd-MRI), DWI and combination of both) were reviewed independently by 3 observers. The areas under the receiver operating characteristic curves (A(z)), sensitivity and specificity for the 3 image sets were compared. The standard of reference was either histopathology or multi-modality and clinical follow-up.
  
  
  RESULTS
  Pooled data showed higher diagnostic accuracy for the combined set (A(z)=0.93) compared to Gd-MRI (p=0.001) and DWI (p<0.0001). No difference was found between the performance of Gd-MRI and DWI (p=0.09). Sensitivity for the combined set was higher than Gd-MRI (p=0.0003) and DWI (p=0.0034). Specificity for DWI was lower than Gd-MRI (p<0.0001) and the combined set (p<0.0001).
  
  
  CONCLUSIONS
  The diagnostic performance of DWI is equal to that of Gd-MRI. DWI alone can be used in patients where gadolinium contrast administration is not allowed. Combination of Gd-MRI and DWI significantly increases diagnostic accuracy.
authors.affiliation: Department of Radiology, GZA Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk, Belgium. christophkenis@hotmail.com
authors.forename: Christoph
authors.initials: C
authors.lastname: Kenis
authors.forename: Filip
authors.initials: F
authors.lastname: Deckers
authors.forename: Bert
authors.initials: B
authors.lastname: De Foer
authors.forename: François
authors.initials: F
authors.lastname: Van Mieghem
authors.forename: Steven
authors.initials: S
authors.lastname: Van Laere
authors.forename: Marc
authors.initials: M
authors.lastname: Pouillon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology*; D008113:Liver Neoplasms / Q000473:pathology* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity